A mixture of poly-γ-glutamic acid and levan ameliorates obesity in high fat diet-induced mice.

Anti-obesity effects of a mixture of poly-γ-glutamic acid (γ-PGA) and levan (PL, 6:4 w/w) were evaluated using C57BL/6 mouse models including normal diet (G1), normal diet containing 5% of PL (G2), high-fat diet (HFD) (G3), HFD with 3% of PL (G4), and HFD with 5% of PL (G5) and followed by breeding 12 weeks. After 12 weeks, the content of epididymal fat and the size of fat cell for test animals were significantly decreased by comparing G3 (p < 0.05). Similarily, contents of serum triglyceride, total cholesterol, LDL cholesterol, insulin and leptin in G5 were significantly decreased than G3. Fat accumulations and inflammatory degrees within liver and fat cells were also decreased in the G5 than G3. In addition 5% PL diet might not have any problems causing liver damages. Conclusively, a mixture of γ-PGA and levan could help to improve obesity and dyslipidemia due to high-fat meals.

Improvement of viscous substance production during Cheonggukjang fermentation added with glycine.

When Bacillus subtilis NB-NUC1 associated with Cheonggukjang fermentation was aerobically grown in a synthetic medium containing 1 to 2% glycine (w/v), cell growth was inhibited in a dose-dependent manner. Subsequently, different concentrations of glycine (0, 1, and 2%) were used in Cheonggukjang fermentation for 96 h at 40 °C. Supplementation of 1% glycine increased extracellular γ-glutamyl transpeptidase (γ-GTPase), responsible for the production of viscous substance. Based on correlation studies, we conclude that the production of viscous substance is correlated with viscous extension (r = 0.867), extracellular proteins contents (r = 0.821), and γ-GTPase activity (r = 0.807). The molecular weight of the viscous substance obtained during Cheonggukjang fermentation by B. subtilis NB-NUC1 was also affected by glycine supplementation. Our results demonstrate that glycine supplementation before solid-state fermentation may increase the mass production of mucilage in food industry.

Secondary Fermented Extract of Chaga-Cheonggukjang Attenuates the Effects of Obesity and Suppresses Inflammatory Response in the Liver and Spleen of High-Fat Diet-Induced Obese Mice.

Cheonggukjang and chaga mushrooms have numerous health benefits, and have been used in alternative medicine. Therefore, a powder mixture of 98: Cheonggukjang and 2: Chaga extracts was fermented with Lactobacillus acidophilus KCTC3925 (FCC) and its anti-obesity effects in high-fat diet (HFD)-induced obese mice were determined. Five-week-old male ICR mice were fed a normal diet or HFD in the presence or absence of 3% and 5% FCC by weight (n = 10 per group). After 12 weeks, the mice were sacrificed, and the serum and tissue samples were collected for analysis. Body weight and epididymal fat pad weight were significantly lowered in the 3% and 5% FCC groups compared with those in the HFD control group (p < 0.01). FCC supplementation suppressed serum triglyceride and increased serum HDL-C levels (p < 0.01). Serum GOT, GPT, and leptin levels, hepatic COX-2 mRNA expression, and splenic COX-2 and IL-4 mRNA expression were significantly higher in the HFD groups than in the control group (p > 0.05); however, except for splenic IL-4 levels, the increases were significantly attenuated by FCC supplementation. Expression of ICAM-1, an aortic inflammatory marker, was significantly increased in the HFD group; this effect was suppressed in the 3% FCC group (p < 0.01) but not in the 5% FCC group. FCC suppressed the body weight and epididymal fat pad weight gain, as well as inflammatory responses in the liver and spleen of HFD-fed mice. Thus, FCC supplementation will be beneficial for the treatment of obesity-related effects.

Aglycone Isoflavones and Exopolysaccharides Produced by Lactobacillus acidophilus in Fermented Soybean Paste.

Bioconversion of aglycone-formed isoflavones from glycoside-formed isoflavones by commercial lactic acid bacteria in fermented soybean paste was evaluated. Enterococcus faecium KCTC 13410 showed the most resistant capacity and Lactobacillus acidophilus KCTC 3925 had a sensitive susceptibility at a high NaCl concentration (13.2%) in fermented soybean paste. Among the 5 strains tested, Lac. acidophilus KCTC 3925 showed the highest relative ratio of aglycone-formed isoflavones to total isoflavones in fermented soybean paste. Production of exopolysaccarides (EPS) by lactic acid bacteria was compared using de Man, Rogosa, and Sharpe medium containing 1% sucrose at 37°C for 48 h. Among the 5 lactic acid bacteria, Lac. acidophilus KCTC 3925 and Lactobacillus rhamnosus KCTC 3929 were investigated to produce EPS. Based on the results concerning growing susceptibility and conversion of aglycone-formed isoflavones/EPS production, it is anticipated that Lac. acidophilus KCTC 3925 may be used for preparation of Cheonggukjang, which contains relative low NaCl content.

Proposed Use of Thickener According to Fluid Intake on Videofluoroscopic Swallowing Studies: Preliminary Study in Normal Healthy Persons.

OBJECTIVE: To examine the characteristics and changes in the pharyngeal phase of swallowing according to fluid viscosity in normal healthy persons, to help determine fluid intake methods in more detail than the use of standardized fluid. METHODS: This was a prospective observational study involving 10 normal healthy adults. While the participants sequentially took in fluids with 10 different viscosities changes in the pharyngeal phase of the swallowing process were monitored using videofluoroscopic swallowing studies (VFSS). Twenty parameters of the pharyngeal phase, including epiglottis contact, laryngeal elevation, pharyngeal constriction, and upper esophageal sphincter opening, were determined and compared. RESULTS: No significant viscosity-based changes in epiglottis contact, laryngeal elevation, or upper esophageal sphincter-opening duration of the pharyngeal phase were observed. However, pharyngeal transit time and time from the start of the pharyngeal phase to peak pharyngeal constriction were significantly delayed upon intake of fluid with viscosities of 150.0 centipoise (cP) and 200.0 cP. CONCLUSION: VFSS analysis of fluid intake may require the use of fluids of various concentrations to determine a suitable viscosity of thickener mixture for each subject.

The analgesic and anti-inflammatory effects of Litsea japonica fruit are mediated via suppression of NF-κB and JNK/p38 MAPK activation.

Fruits of the Litsea family of trees and shrubs contain biologically active compounds, some of which have been used as natural nutrients and flavoring agents in food. In this study, we identified novel anti-nociceptive effects of the 30% ethanol extract, the CH(2)Cl(2) fraction and the associated active components (Hamabiwalactone A and B) from Litsea japonica fruit by using in vivo peripheral and central nervous pain models. In addition, we compared the anti-inflammatory effects of several fractions from L. japonica fruit extracts using lipopolysaccharide (LPS)-stimulated Raw264.7 cells. The CH(2)Cl(2) fraction of L. japonica fruit (LJM) had an optimal combination of anti-inflammatory effects and low cytotoxicity. Dose response studies were performed to determine the inhibitory effects of LJM on the pro-inflammatory enzymes, COX-2/PGE(2) and NO/iNOS, and pro-inflammatory cytokines, IL-1ß, IL-6, and TNF-α. Molecular profiling revealed that LJM exerts anti-inflammatory effects through inhibition of NF-κB and JNK/p38 MAPK signaling in LPS-induced macrophages. This study suggests that CH2Cl2 fraction of L. japonica fruit and its bioactive components are potential candidates as anti-inflammatory and analgesic agents (painkillers) for the treatment of inflammatory diseases.

Anti-inflammatory effects of botulinum toxin type a in a complete Freund's adjuvant-induced arthritic knee joint of hind leg on rat model.

The objective of the study is to verify histopathologically the anti-inflammatory effect of botulinum toxin type A (BoNT-A) in a Complete Freund's Adjuvant (CFA)-induced arthritic knee joint of hind leg on rat model using immunofluorescent staining of anti-ionized calcium-binding adaptor molecule 1 (Iba-1) and interleukin-1ß (IL-1ß) antibody. Twenty-eight experimental rats were injected with 0.1 ml of CFA solution in the knee joint of the hind leg bilaterally. Three weeks after CFA injection, the BoNT-A group (N = 14) was injected with 20 IU (0.1 ml) of BoNT-A bilaterally while the saline group (N = 14) was injected with 0.1 ml of saline in the knee joint of the hind leg bilaterally. One and two weeks after BoNT-A or saline injection, joint inflammation was investigated in seven rats from each group using histopathological and immune-fluorescent staining of Iba-1 and IL-1ß antibody. The number of Iba-1 and IL-1ß immune-reactive (IR) cells was counted in the BoNT-A and saline groups for comparison. There was a significant reduction in joint inflammation and destruction in the BoNT-A group at 1 and 2 weeks after BoNT-A injection compared with the saline group. The binding of Iba-1 and IL-1ß antibody was significantly lower in the BoNT-A group than the saline group at 1 and 2 weeks after BoNT-A injection. The number of Iba-1 and IL-1ß-IR cells at 1 and 2 weeks after the injection of BoNT-A were significantly different from the corresponding number of Iba-1 and IL-1ß-IR cells in the saline group. To conclude, BoNT-A had an anti-inflammatory effect in a CFA-induced arthritic rat model, indicating that BoNT-A could potentially be used to treat inflammatory joint pain.

Effects of ß-glucans from Coriolus versicolor on macrophage phagocytosis are related to the Akt and CK2/Ikaros.

Coriolus versicolor has been known to be an immune stimulator effects. For further understanding of the phagocytic activity and the intracellular mechanisms of ß-glucan from C. versicolor (CVG), we examined the phagocytic activity, phosphorylation of Akt and CK2, nucleus translocation of p65 and Ikaros activity in ß-glucan-treated macrophages using RT-PCR, western blotting, and IP assay. The role of Ikaros in regulating phagocytic effects of CVG was also determined using Ikaros dominant negative isoform cells. This study suggests that CK2/Ikaros are positive regulators and novel signaling pathway involved in phagocytosis and contributes to elucidating the mechanism underlying phagocytic activity induced by ß-glucan.

Quality characteristics and ginsenosides composition of ginseng-yakju according to the particle size of ginseng powder.

The aim of this study was to develop rice wine (Yakju) containing various amounts and particle sizes of ginseng powder and to analyze the physicochemical characteristics and content of ginsenosides in ginseng-Yakju. Soluble solid content, pH, ethanol concentration, acidity, amino acid content, and evaluation of preference showed no difference between four kinds of Yakju groups, regardless of ginseng supplementation and particle size of the ginseng powder. During fermentation of Yakju containing ginseng, the contents of ginsenosides Rb1, Rb2, Rb3, and Rc were decreased. Otherwise, the content of ginsenoside Rh1 was increased highly by brewing microorganisms in Yakju. Recovery ratios of ginsenosides in ginseng-Yakju were approximately 25.4% (coarse ginseng power) and 23.8% (fine ginseng powder), which were superior to the recovery ratio of ginsenosides in Yakju containing ginseng slices (5%).

Magnesium supplementation through seaweed calcium extract rather than synthetic magnesium oxide improves femur bone mineral density and strength in ovariectomized rats.

Commercially available seaweed calcium extract can supply high amounts of calcium as well as significant amounts of magnesium and other microminerals. The purpose of this study was to investigate the degree to which the high levels of magnesium in seaweed calcium extract affects the calcium balance and the bone status in ovariectomized rats in comparison to rats supplemented with calcium carbonate and magnesium oxide. A total of 40 Sprague-Dawley female rats (7 weeks) were divided into four groups and bred for 12 weeks: sham-operated group (Sham), ovariectomized group (OVX), ovariectomized with inorganic calcium and magnesium supplementation group (OVX-Mg), and ovariectomized with seaweed calcium and magnesium supplementation group (OVX-SCa). All experimental diets contained 0.5% calcium. The magnesium content in the experimental diet was 0.05% of the diet in the Sham and OVX groups and 0.1% of the diet in the OVX-Mg and OVX-SCa groups. In the calcium balance study, the OVX-Mg and OVX-SCa groups were not significantly different in calcium absorption compared to the OVX group. However, the femoral bone mineral density and strength of the OVX-SCa group were higher than those of the OVX-Mg and OVX groups. Seaweed calcium with magnesium supplementation or magnesium supplementation alone did not affect the serum ALP and CTx levels in ovariectomized rats. In summary, consumption of seaweed calcium extract or inorganic calcium carbonate with magnesium oxide demonstrated the same degree of intestinal calcium absorption, but only the consumption of seaweed calcium extract resulted in increased femoral bone mineral density and strength in ovariectomized rats. Our results suggest that seaweed calcium extract is an effective calcium and magnesium source for improving bone health compared to synthetic calcium and magnesium supplementation.

Effects of korean red ginseng extract for the treatment of atopic dermatitis-like skin lesions in mice.

Atopic dermatitis (AD) is an allergic, inflammatory skin disease characterized by chronic eczema and mechanical injury to the skin, caused by scratching. Korean red ginseng (RG) has diverse biological activities, but the molecular effects of RG on allergic diseases, like AD, are unclear. The present study was designed to investigate whether RG inhibits 1-chloro-2,4-dinitrobenzene (DNCB)-induced AD in a mouse model. DNCB was applied topically on the dorsal surface of Balb/c mice to induce AD-like skin lesions. We observed the scratching behavior and examined the serum IgE level and interleukin (IL)-4 and IL-10 in splenocytes compared with dexamethasone. We also evaluated the DNCB-induced mitogen-activated protein kinases (MAPKs), NF-κB, and Ikaros activities after RG treatment using reverse transcriptase-polymerase chain reaction, Western blotting, and ELISA. Our data showed that the topical application of RG significantly improved the AD-like skin lesions and scratching behavior. RG decreased not only the mRNA expression of IL-4 and IL-10, but also the secretion of IL-4 protein and serum IgE in mice. Additionally, RG treatment decreased the DNCB-induced MAPKs activity and subsequent Ikaros translocation irrespective of NF-κB. We suggest that RG may be useful as a therapeutic nutrition for the treatment of AD.

Neuroprotective effects of consuming bovine colostrum after focal brain ischemia/reperfusion injury in rat model.

To investigate the neuroprotective effects of bovine colostrums (BC), we evaluate the ability of consuming BC after focal brain ischemia/reperfusion injury rat model to reduce serum cytokine levels and infarct volume, and improve neurological outcome. Sprague-Dawley rats were randomly divided into 4 groups; one sham operation and three experimental groups. In the experimental groups, MCA occlusion (2 h) and subsequent reperfusion (O/R) were induced with regional cerebral blood flow monitoring. One hour after MCAO/R and once daily during the experiment, the experimental group received BC while the other groups received 0.9% saline or low fat milk (LFM) orally. Seven days later, serum pro-inflammatory cytokine (IL-1beta, IL-6, and TNF-alpha) and anti-inflammatory cytokine (IL-10) levels were assessed. Also, the infarct volume was assessed by using a computerized image analysis system. Behavioral function was also assessed using a modified neurologic severity score and corner turn test during the experiment. Rats receiving BC after focal brain I/R showed a significant reduction (-26%/-22%) in infarct volume compared to LFM/saline rats, respectively (P < 0.05). Serum IL-1beta, IL-6, and TNF-alpha levels were decreased significantly in rats receiving BC compared to LFM/saline rats (P < 0.05). In behavioral tests, daily BC intake showed consistent and significant improvement of neurological deficits for 7 days after MCAO/R. BC ingestion after focal brain ischemia/reperfusion injury may prevent brain injury by reducing serum pro-inflammatory cytokine levels and brain infarct volume in a rat model.

Production of lactosucrose from sucrose and lactose by a levansucrase from Zymomonas mobilis.

Lactosucrose (4(G)-beta-D-galactosylsucrose) is an oligosaccharide consisting of galactose, glucose, and fructose. In this study, we prepared lactosucrose from lactose and sucrose using a levansucrase derived from Zymomonas mobilis. Optimum conditions for lactosucrose formation were 23 degrees C, pH 7.0, 18.0% (w/v) lactose monohydrate, and 18% (w/v) sucrose as substrates, and 1 unit of enzyme/ml of reaction mixture. Under these conditions, the lactosucrose conversion efficiency was 28.5%. The product was purified and confirmed to be O-beta-D-galactopyranosyl-(1-->4)-O-beta-D-glucopyranosyl- (1-->2)-beta-D-fructofuranoside, or lactosucrose. A mixed-enzyme system containing a levansucrase and a glucose oxidase was applied in order to increase the efficiency of lactose and sucrose conversion to lactosucrose, which rose to 43.2% as s result.

Bovine colostrum prevents bacterial translocation in an intestinal ischemia/reperfusion-injured rat model.

This study evaluated whether or not bovine colostrum (BC) is able to treat or prevent intestinal barrier damage, bacterial translocation, and the related systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS) in an intestinal ischemia/reperfusion (I/R)-injured rat model. Fifty Sprague-Dawley rats were used. The rats' intestinal I/R injuries were induced by clamping the superior mesenteric artery for 30 minutes. After 3 hours of reperfusion and then twice daily reclamping during the experiment, the experimental group was given BC (4 mL/kg/day) perorally, and the other groups received 0.9% saline and low fat milk (LFM) after intestinal I/R injury. Seventy-two hours later we assessed (1) intestinal damage and intestinal permeability, (2) enteric bacterial count and bacterial translocation, (3) serum albumin, protein, and hepatic enzyme levels, (4) pathologic findings of ileum and lung, (5) activity of oxygen-free radical species, and (6) pro-inflammatory cytokines (tumor necrosis factor-alpha and interleukin-1beta). Intestinal damage, intestinal permeability, and bacterial translocation to other organs were significantly reduced in rats fed with BC after I/R when compared to rats fed LFM/saline after I/R (P < .05). In the evaluation of acute lung injury, neutrophils were found only in the lungs of the saline-fed group after I/R, and the wet/dry ratio of the lung tissue was significantly reduced in the BC-fed group after I/R compared to other I/R groups. A marked difference was found between LFM/saline-fed groups and BC-fed groups regarding malondialdehyde (P < .05) and pro-inflammatory cytokines (P < .01). In conclusion, BC may have beneficial effects in treating and preventing intestinal barrier damage, bacterial translocation and the related SIRS and MODS in the intestinal I/R-injured rat model.

Panax ginseng protects against global ischemia injury in rat hippocampus.

Based on the use of Panax ginseng C.A. Meyer (Family Araliaceae) for the treatment of stroke in traditional Korean medicine, the present study was carried out to evaluate neuroprotective effects of P. ginseng after transient global cerebral ischemia using the four-vessel occlusion rat model. Nissl staining, lipid peroxidation (malondialdehyde [MDA] formation), and activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) of rat brain were assessed. Ethanolic P. ginseng extract (200 mg/kg, i.p.) significantly protected CA1 neurons against 10 minutes of transient forebrain ischemia as demonstrated by measuring the density of neuronal cells. P. ginseng also significantly decreased the level of MDA and increased the expression of GPx and SOD. These results suggest that P. ginseng might be neuroprotective against cerebral ischemia-induced injury in rat brain by decreasing lipid peroxides and increasing the expression of GPx and SOD.

beta-Glucan enhanced apoptosis in human colon cancer cells SNU-C4.

The apoptotic effect of bacteria-derived beta-glucan was investigated in human colon cancer cells SNU-C4 using terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay, reverse transcription-polymerase chain reaction (RT-PCR) expressions of Bcl-2, Bax, and Caspase-3 genes, and assay of caspase-3 enzyme activity. beta-Glucan of 10, 50, and 100 microg/mL decreased cell viability in a dose-dependent manner with typical apoptotic characteristics, such as morphological changes of chromatin condensation and apoptotic body formation from TUNEL assay. In addition, beta-glucan (100 microg/mL) decreased the expression of Bcl-2 by 0.6 times, whereas the expression of Bax and Caspase-3 were increased by 3.1 and 2.3 times, respectively, compared to untreated control group. Furthermore, the caspase-3 activity in the beta-glucan-treated group was significantly increased compared to those in control group (P < 0.05). Bacterial derived beta-glucan could be used as an effective compound inducing apoptosis in human colon cancer.

Isolation and characterization of marine bacterial strain degrading fucoidan from Korean Undaria pinnatifida Sporophylls.

In spite of an increasing interest in fucoidans as biologically active compounds, no convenient commercial sources with fucoidanase activity are yet available. A marine bacterial strain that showed confluent growth on a minimal medium containing fucoidan, prepared from Korean Undaria pinnatifida sporophylls, as the sole carbon source was isolated and identified based on a 16S rDNA sequence analysis as a strain of Sphingomonas paucimobilis, and named Sphingomonas paucimobilis PF-1. The strain depolymerized fucoidan into more than 7 distinct lowmolecular- mass fucose-containing oligosaccharides, ranging from 305 to 3,749 Da. The enzyme activity was shown to be associated with the whole cell, suggesting the possibility of a surface display of the enzyme. However, a whole-cell enzyme preparation neither released the monomer Lfucose from the fucoidan nor hydrolyzed the chromogenic substrate p-nitrophenyl-alpha-L-fucoside, indicating that the enzyme may be an endo-acting fucoidanase rather than an alpha-L-fucosidase. Therefore, this would appear to be the first report on fucoidanolytic activity by a Sphingomonas species and also the first report on the enzymatic degradation of the Korean Undaria pinnatifida sporophyll fucoidan. Moreover, this enzyme activity may be very useful for structural analyses of fucose-containing polysaccharides and the production of bioactive fucooligosaccharides.

Altered mRNA expression of hepatic lipogenic enzyme and PPARalpha in rats fed dietary levan from Zymomonas mobilis.

Levan or high molecular beta-2,6-linked fructose polymer is produced extracellularly from sucrose-based substrates by bacterial levansucrase. In the present study, to investigate the effect of levan feeding on serum leptin, hepatic lipogenic enzyme and peroxisome proliferation-activated receptor (PPAR) alpha expression in high-fat diet-induced obese rats, 4-week-old Sprague-Dawley male rats were fed high-fat diet (beef tallow, 40% of calories as fat), and, 6 weeks later, the rats were fed 0%, 1%, 5% or 10% levan-supplemented diets for 4 weeks. Serum leptin and insulin level were dose dependently reduced in levan-supplemented diet-fed rats. The mRNA expressions of hepatic fatty acid synthase and acetyl CoA carboxylase, which are the key enzymes in fatty acid synthesis, were down-regulated by dietary levan. However, dietary levan did not affect the gene expression of hepatic malic enzyme, phosphatidate phosphohydrolase and HMG CoA reductase. Also, the lipogenic enzyme gene expression in the white adipose tissue (WAT) was not affected by the diet treatments. However, hepatic PPARalpha mRNA expression was dose dependently up-regulated by dietary levan, whereas PPARgamma in the WAT was not changed. The results suggest that the in vivo hypolipidemic effect of dietary levan, including anti-obesity and lipid-lowering, may result from the inhibition of lipogenesis and stimulation of lipolysis, accompanied with regulation of hepatic lipogenic enzyme and PPARalpha gene expression.

Levan fructotransferase from Arthrobacter oxydans J17-21 catalyzes the formation of the di-D-fructose dianhydride IV from levan.

A new levan fructotransferase (LFTase) isolated from Arthrobacter oxydans J17-21 was characterized for the production of difructose dianhydride IV (DFA IV). LFTase was purified to apparent homogeneity by Q-Sepharose ion exchange chromatography, Mono-Q HR 5/5 column chromatography, and gel permeation chromatography. The enzyme had an apparent molecular mass of 54000 Da. The optimum pH for the enzyme-catalyzed reaction was pH 6.5, and the optimum temperature was observed at 45 degrees C. The LFTase was activated by the presence of CaCl(2) and EDTA-2Na but inhibited strongly by MnCl(2) and CuSO(4) at 1 mM and completely by FeSO(4) and Ag(2)SO(4) at 1 mM. A bacterial levan from Zymomonas mobilis was incubated with an LFTase; final conversion yield from the levan to DFA IV was 35%. Neither inulin, levanbiose, sucrose, dextran, nor starch was hydrolyzed by LFTase. DFA IV was very stable at acidic pH and high temperature, thus indicating that DFA IV may be suitable for the food industry and related areas.

Molecular characterization of the growth phase-dependent expression of the lsrA gene, encoding levansucrase of Rahnella aquatilis.

Expression of the lsrA gene from Rahnella aquatilis, encoding levansucrase, is tightly regulated by the growth phase of the host cell; low-level expression was observed in the early phase of cell growth, but expression was significantly stimulated in the late phase. Northern blot analysis revealed that regulation occurred at the level of transcription. The promoter region was identified by primer extension analysis. Two opposite genetic elements that participate in the regulation of lsrA expression were identified upstream of the lsrA gene: the lsrS gene and the lsrR region. The lsrS gene encodes a protein consisting of 70 amino acid residues (M(r), 8,075), which positively activated lsrA expression approximately 20-fold in a growth phase-dependent fashion. The cis-acting lsrR region, which repressed lsrA expression about 10-fold, was further narrowed to two DNA regions by deletion analysis. The concerted action of two opposite regulatory functions resulted in the growth phase-dependent activation of gene expression in Escherichia coli independent of the stationary sigma factor sigma(S).